In historical terms, energy is very very cheap, so cheap that it is quite difficult to make accurate comparisons.
Let’s survey some transitions that have occurred in human use of energy.
Pre-human great apes, like all other animals, used only the energy derived from food they consumed, and hence ultimately derived from current solar output as captured by photosynthesis.
Hundreds of thousands of years ago, possibly before Homo sapiens proper emerged, our ancestors learned to control fire, for cooking and tool-making, and raising the possibility of heating enclosed living spaces (though this didn’t happen until much later). At this point our overall energy use is no longer limited by what we can eat. Nor is it limited by current solar output: trees can be harvested that have taken many years to grow. It is entirely possible for a culture to deforest its landbase and collapse.
In a later transformative event, we learned to harness large animals for traction (including pulling plows) and for riding. This gave access to more power, or more speed, than we could muster on our own, but all this energy was still ultimately derived from photosynthesis.
And then there is fossil fuel, whereby we take advantage of biological and geological processes operating on very long time scales that have concentrated many years’ worth of photosynthetic energy into an easily burned form. The use of peat and outcrop coal goes back millennia, but of course things really took off in the last few centuries, with coal mining and later oil and gas drilling.
Although fossil fuel has been and still is used directly to produce heat, our desire for it has been greatly amplified by other modes of use: to produce motion, and via motion to produce electricity.
One way to understand the current cheapness of energy is to contemplate the difference between possession and use of a car, something available in the ‘rich’ part of the world to all but the poorest citizens, and the likely state of things if no fossil fuel had ever existed: as in past centuries, if you were sufficiently rich you might own one or more horses, to ride or pull carriages, and if you were less well-off you could hire a horse or horse-drawn conveyance on an occasional basis. Horses need feeding: it takes about five acres in grass to feed a horse. And you do not get speeds of 70 miles an hour from a horse.